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Malcolm
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Just been thinking about getting a 2x TC for my Canon 70-200 f2.8 lens and wondered about reports from anyone having used this - either the Canon or the Kenko models.

Also anyone coupled both the 2x and the 1.4x together?:shrug:
 
I have a Kenko MC-7 x2 extender attached to my Sigma 70-200 f/2.8 EX II which I bought specifically for the F1 practice at Silverstone tomorrow.

I heard about loss of IQ, light drop off and slower AF so yesterday I gave it a thorough test.

My Conclusions;

1 - drop off in light. They say you lose 1 stop. Ironic then that with the kenko and the Siggy, my 50d overexposes by exactly 1 stop, so when I dial down the exposure compensation I get this back, lol! So no real issue there!

2 - IQ. The IQ is still very good indeed. The only issue is the longer length and lack of IS/OS (I have the non stablised Siggy) its harder to keep the frame steady but this wont be an issue! I did notice the bokeh wasnt quite as nice with the TC but thats only a minor issue.

3 - AF. There is a slight drop in AF speed and it can hunt in low light. However, outside where I will obviously use this, the focusing is still fast and I could easily track seagulls in flight yesterday.

My conclusions are very favorable towards the Kenko x2 extender, and I can only assume the Canon is even better! A very worthwhile investment IMO (and I got mine used for £80!) but the real test comes tomorrow!

I dont know if you can place the 1.4 and 2x together, but even if you could, I wouldnt want to!!
 
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1 - drop off in light. They say you lose 1 stop. Ironic then that with the kenko and the Siggy, my 50d overexposes by exactly 1 stop, so when I dial down the exposure compensation I get this back, lol! So no real issue there!

2x extenders mean a 2 stop loss of light. (Because the focal length is 2x but the aperture remains the same size).
 
2x extenders mean a 2 stop loss of light. (Because the focal length is 2x but the aperture remains the same size).

Ah yes, very true. I still cant understand my 50d overexposing. Well, actually its probably over meeting rather than exposing so theres a little false pretense going on I feel! Still have to dial the comp down to -2 though!

Anyway, for the OP, here are a few shots that I've taken using the x2 extender with AI servo focus in average light conditions;


Sailing boat by Odd Jim, on Flickr


Stella by Odd Jim, on Flickr


gull flying by Odd Jim, on Flickr


IMG_1471 by Odd Jim, on Flickr

Not too shabby!
 
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Hi Jim,

thanks for the info. I had seen some of your comment on another thread and the additional shots are great. I think that from other comments on TC's I have read, the Canon gives a slightly sharper centre than the Kenco, but not much in it.

I borrowed a 100-400 lens a week ago for a Safari shoot at Woburn and it made a hell of a difference to my 70-200, so thought I would try a converter.

I also read some time ago that reasonable results had been obtained joining the 2x and the 1.4x behind a lens and was trying to hear from someone who may have tried this and ideally the difference in linking the Kenco and the Cannon's to see which performs best.

Initially may look for the 2x and see if I can borrow a 1.4 to see results.

Thanks again and good shooting with the new TC

Malcolm
 
:thumbs: glad it helped.
 
Thanks Adam.

I appreciate the light loss, which would be greater if coupling both the 1.4 and the 2x converters, so I would loose 3 stops from the F2.8 70-200.
 
I have the tamron 70-200 and Kenko Pro 300 DGX 1.4x Tc and Pro 300 DG 2x tc.

I find the 1.4x Tc to be great and have no qualms about using it. The 2x tc I find needs good light as I struggle to keep the shutter speed up. It also helps to be able to stop down a little too.

I have only once used them stacked, on a tripod, but on mud trying to photograph flamingoes miles away. There was no wind (possibly a little breeze, but as it was 12 months ago, I can't honestly remember), and on a 190xprob with 486rc2. The image was bouncing around a fair bit in the viewfinder and coupled with it being around 7:30am I struggled to get a high enough shutter speed using an ISO that didn't give too much noise.

1.4x tc:

40D, ISO 400, f6.3, 1/640, 280mm, handheld, cropped
991224656_Gny5H-M.jpg


40D, ISO 400, f4, 1/3200, 98mm, handheld, full frame
991222732_yPehP-M.jpg


2x tc:

40D, ISO 1000, f5.6, 1/500, 400mm, handheld (well, elbows resting on a shelf in a hide, but not well braced), quite a large crop if I remember correctly
1063601836_99FKy-M.jpg


Can't find any others off hand (my 2x tc is a non reporting one, so checking Exif doesn't help!) Hope that helps though.
 
Thanks for the info Gema (?)

and for the shots. I also like shots in your gallery, particularly the leopard in Botswana and the wood workshop in Venice. We will be in Venice in September for the first time and hope to find such interesting places. Was the workshop on a conducted tour. or did you just stumble upon it?

I hope to try the 1.4 and the 2x before buying and it would be good to couple them if possible, but this may not really be practical for more than the odd shot

Malcolm
 
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Thanks for the comments on my photos!

The woodworkshop was making gondola oars I seem to remember. I just stumbled upon it tbh, can't remember where it was now. Venice is a lovely city and well worth just wandering around IMO. Get to the touristy things early to avoid the ques though!
 
Thanks Gemma,

we are doing a cruise and have 24 hours in Venice. I will ask about the oar workshop, it is a very interesting place and your shot is great.

Best wishes

Malcolm
 
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